Mass balance and thermodynamic description of solid state fermentation of lignocellulosics byPleurotus ostreatus for animal feed production

This study was focused primarily on the degradation of lignin in water hyacinth and barley straw for animal-feed production. The experiment was performed in a 1.5-L Applikon fermenter for 30 days, varying the air flow rate from 0.022 VVM/0.047 VMM to 0.048 VVM/0.102 VMM. A novel approach was introduced for prediction of a kinetic model by using instantaneous respiratory quotient (RQ) measurements and steady state elemental balances. Growth kinetics were determined for the fungus in a 30-day fermentation with a mixture of barley straw and water hyacinth as the substrate. The instantaneous heat-interaction profile was predicted from steady state balances. Fermentation data were checked for consistency using the entropy balance inequality, and thermodynamic efficiency was calculated to show that degradation of lignocellulosics byPleurotus ostreatus followed more than one metabolic pathway during the course of the fermentation. Growth ofP. ostreatus on lignocellulosics, such as water hyacinth and barley straw, was di-auxic or possibly tri-auxic during the 30 days of fermentation.     

Boundary Conditions for Heat Transfer and Evaporative Cooling in the Trachea and Air Sac System of the Domestic Fowl: A Two-Dimensional CFD Analysis

Various parts of the respiratory system play an important role in temperature control in birds. We create a simplified computational fluid dynamics (CFD) model of heat exchange in the trachea and air sacs of the domestic fowl (Gallus domesticus) in order to investigate the boundary conditions for the convective and evaporative cooling in these parts of the respiratory system. The model is based upon published values for respiratory times, pressures and volumes and upon anatomical data for this species, and the calculated heat exchange is compared with experimentally determined values for the domestic fowl and a closely related, wild species. In addition, we studied the trachea histologically to estimate the thickness of the heat transfer barrier and determine the structure and function of moisture-producing glands. In the transient CFD simulation, the airflow in the trachea of a 2-dimensional model is evoked by changing the volume of the simplified air sac. The heat exchange between the respiratory system and the environment is simulated for different ambient temperatures and humidities, and using two different models of evaporation: constant water vapour concentration model and the droplet injection model. According to the histological results, small mucous glands are numerous but discrete serous glands are lacking on the tracheal surface. The amount of water and heat loss in the simulation is comparable with measured respiratory values previously reported. Tracheal temperature control in the avian respiratory system may be used as a model for extinct or rare animals and could have high relevance for explaining how gigantic, long-necked dinosaurs such as sauropoda might have maintained a high metabolic rate.     

Partitioning of transpiratory water loss of the desert scorpion, Hadrurus arizonensis (Iuridae)

Terrestrial arthropods lose body water to the environment mainly through transpiration. The aim of this study was to determine the fraction of respiratory losses from total transpiratory water loss in scorpions, as relatively high respiratory losses would indicate a fitness benefit from regulation of gas-exchange rate under stressful desiccating conditions. We measured metabolic rates and water-loss rates of Hadrurus arizonensis (Iuridae) at a range of ecologically-relevant temperatures. Calculation of respiratory water losses was based on increased metabolic and water-loss rates during nocturnal activity (assuming no change in cuticular resistance at a given constant experimental temperature). Respiratory losses accounted for 9.0 ± 1.7% of total transpiratory losses at 25 °C, doubled to 17.9 ± 1.8% at 30 °C and increased to 31.0 ± 2.0% at 35 °C (n = 5, 15 and 15, respectively). Furthermore, the relative importance of respiratory transpiration is likely to be higher at temperatures above 35 °C, which have been recorded even within the burrows of H. arizonensis. Measurements of cuticular lipid melting points do not provide evidence for increased cuticular resistance to water loss at higher temperatures. However, the relatively high fraction of respiratory water losses reported here for H. arizonensis supports the notion of respiratory regulation as an evolved mechanism for conserving scorpion body water stores under stressful conditions.     

A Model of Respiratory Heat Transfer in a Small Mammal

A steady-state model of the heat and water transfer occurring in the upper respiratory tract of the kangaroo rat, Dipodomys spectabilis, is developed and tested. The model is described by a steady-state energy balance equation in which the rate of energy transfer from a liquid stream (representing the flow of heat and blood from the body core to the nasal region) is equated with the rate of energy transfer by thermal conduction from the nose tip to the environment. All of the variables in the equation except the flow rate of the liquid stream can be either measured directly or estimated from physiological measurements, permitting the solution of the equation for the liquid stream flow rate. After solving for the liquid stream flow rate by using data from three animals, the energy balance equation is used to compute values of energy transfer, expired air temperature, rates of water loss, and efficiency of vapor recovery for a variety of ambient conditions. These computed values are compared with values measured or estimated from physiological measurements on the same three animals, and the equation is thus shown to be internally consistent. To evaluate the model's predictive value, calculated expired air temperatures are compared with measured expired air temperatures of eight additional animals. Finally, the model is used to examine the general dependence of expired air temperature, of rates of water loss, and of efficiency of vapor recovery on ambient conditions.     

A theoretical model of localized heat and water vapor transport in the human respiratory tract

A steady-state, one-dimensional theoretical model of human respiratory heat and water vapor transport is developed. Local mass transfer coefficients measured in a cast replica of the upper respiratory tract are incorporated into the model along with heat transfer coefficients determined from the Chilton-Colburn analogy and from data in the literature. The model agrees well with reported experimental measurements and predicts that the two most important parameters of the human air-conditioning process are: the blood temperature distribution along the airway walls, and the total cross-sectional area and perimeter of the nasal cavity. The model also shows that the larynx and pharynx can actually gain water over a respiratory cycle and are the regions of the respiratory tract most subject to drying. With slight modification, the model can be used to investigate respiratory heat and water vapor transport in high stress environments, pollutant gas uptake in the respiratory tract, and the connection between respiratory air-conditioning and the function of the mucociliary escalator.     

S. mansoni Bolsters Anti-Viral Immunity in the Murine Respiratory Tract

The human intestinal parasite Schistosoma mansoni causes a chronic disease, schistosomiasis or bilharzia. According to the current literature, the parasite induces vigorous immune responses that are controlled by Th2 helper cells at the expense of Th1 helper cells. The latter cell type is, however, indispensable for anti-viral immune responses. Remarkably, there is no reliable literature among 230 million patients worldwide describing defective anti-viral immune responses in the upper respiratory tract, for instance against influenza A virus or against respiratory syncitial virus (RSV). We therefore re-examined the immune response to a human isolate of S. mansoni and challenged mice in the chronic phase of schistosomiasis with influenza A virus, or with pneumonia virus of mice (PVM), a mouse virus to model RSV infections. We found that mice with chronic schistosomiasis had significant, systemic immune responses induced by Th1, Th2, and Th17 helper cells. High serum levels of TNF-α, IFN-γ, IL-5, IL-13, IL-2, IL-17, and GM-CSF were found after mating and oviposition. The lungs of diseased mice showed low-grade inflammation, with goblet cell hyperplasia and excessive mucus secretion, which was alleviated by treatment with an anti-TNF-α agent (Etanercept). Mice with chronic schistosomiasis were to a relative, but significant extent protected from a secondary viral respiratory challenge. The protection correlated with the onset of oviposition and TNF-α-mediated goblet cell hyperplasia and mucus secretion, suggesting that these mechanisms are involved in enhanced immune protection to respiratory viruses during chronic murine schistosomiasis. Indeed, also in a model of allergic airway inflammation mice were protected from a viral respiratory challenge with PVM.     

The Campylobacter jejuni NADH:ubiquinone oxidoreductase (complex I) utilizes flavodoxin rather than NADH

Campylobacter jejuni encodes 12 of the 14 subunits that make up the respiratory enzyme NADH:ubiquinone oxidoreductase (also called complex I). The two nuo genes not present in C. jejuni encode the NADH dehydrogenase, and in their place in the operon are the novel genes designated Cj1575c and Cj1574c. A series of mutants was generated in which each of the 12 nuo genes (homologues to known complex I subunits) was disrupted or deleted. Each of the nuo mutants will not grow in amino acid-based medium unless supplemented with an alternative respiratory substrate such as formate. Unlike the nuo genes, Cj1574c is an essential gene and could not be disrupted unless an intact copy of the gene was provided at an unrelated site on the chromosome. A nuo deletion mutant can efficiently respire formate but is deficient in α-ketoglutarate respiratory activity compared to the wild type. In C. jejuni, α-ketoglutarate respiration is mediated by the enzyme 2-oxoglutarate:acceptor oxidoreductase; mutagenesis of this enzyme abolishes α-ketoglutarate-dependent O₂ uptake and fails to reduce the electron transport chain. The electron acceptor for 2-oxoglutarate:acceptor oxidoreductase was determined to be flavodoxin, which was also determined to be an essential protein in C. jejuni. A model is presented in which CJ1574 mediates electron flow into the respiratory transport chain from reduced flavodoxin and through complex I.     

Time-Varying Respiratory System Elastance: A Physiological Model for Patients Who Are Spontaneously Breathing

Background

Respiratory mechanics models can aid in optimising patient-specific mechanical ventilation (MV), but the applications are limited to fully sedated MV patients who have little or no spontaneously breathing efforts. This research presents a time-varying elastance (E_drs) model that can be used in spontaneously breathing patients to determine their respiratory mechanics.

Methods

A time-varying respiratory elastance model is developed with a negative elastic component (E_demand), to describe the driving pressure generated during a patient initiated breathing cycle. Data from 22 patients who are partially mechanically ventilated using Pressure Support (PS) and Neurally Adjusted Ventilatory Assist (NAVA) are used to investigate the physiology relevance of the time-varying elastance model and its clinical potential. E_drs of every breathing cycle for each patient at different ventilation modes are presented for comparison.

Results

At the start of every breathing cycle initiated by patient, E_drs is < 0. This negativity is attributed from the E_demand due to a positive lung volume intake at through negative pressure in the lung compartment. The mapping of E_drs trajectories was able to give unique information to patients’ breathing variability under different ventilation modes. The area under the curve of E_drs (AUCE_drs) for most patients is > 25 cmH₂Os/l and thus can be used as an acute respiratory distress syndrome (ARDS) severity indicator.

Conclusion

The E_drs model captures unique dynamic respiratory mechanics for spontaneously breathing patients with respiratory failure. The model is fully general and is applicable to both fully controlled and partially assisted MV modes.     

Linkage between diet humidity,metabolic water production and heat dissipation in the larvae of Galleria mellonella

Last instar Galleria larvae respond to a decrease of dietary water content from 12 to 1% by reducing their energetic net growth efficiency from 42.5 to 36.3%. This reduction is linked to increased production of metabolic water, the proportion of which in total water requirement increases from 57 to 97%. Fluctuations in metabolic water output are controlled by changes in oxidative catabolism of the same type of substrates (respiratory quotient is identical under different water regimes). Elevated generation of metabolic water is associated with increased metabolic flow and with enhanced uncoupling of mitochondrial respiration from oxidative phosphorylation. The uncoupling allows for large and variable production of metabolic water in insects adapted to dry environments: the relative degree of uncoupling is 43.3% in Cydia larvae, which live in excess water, but 52.3% in the larvae of Ephestia, which live on a dry substrate; fluctuations between 54.4 and 59.6% in the larvae of Galleria depend on dietary moisture and larval age.     

Pressure oscillation delivery to the lung: Computer simulation of neonatal breathing parameters

Preterm newborn infants may develop respiratory distress syndrome (RDS) due to functional and structural immaturity. A lack of surfactant promotes collapse of alveolar regions and airways such that newborns with RDS are subject to increased inspiratory effort and non-homogeneous ventilation. Pressure oscillation has been incorporated into one form of RDS treatment; however, how far it reaches various parts of the lung is still questionable. Since in-vivo measurement is very difficult if not impossible, mathematical modeling may be used as one way of assessment. Whereas many models of the respiratory system have been developed for adults, the neonatal lung remains essentially ill-described in mathematical models. A mathematical model is developed, which represents the first few generations of the tracheo-bronchial tree and the 5 lobes that make up the premature ovine lung. The elements of the model are derived using the lumped parameter approach and formulated in Simulink? within the Matlab? environment. The respiratory parameters at the airway opening compare well with those measured from experiments. The model demonstrates the ability to predict pressures, flows and volumes in the alveolar regions of a premature ovine lung.     

Immunolocalization of aquaporins 1, 3, and 5 in the nasal respiratory mucosa of a panting species,the sheep (Ovis aries)

The nasal respiratory mucosa is the primary site for evaporative water loss in panting species, necessitating the movement of water across the nasal epithelium. Aquaporins (AQP) are protein channels that facilitate water movement in various fluid transporting tissues of non-panting species. Whether the requirement for enhanced capacity for transepithelial water movement in the nasal respiratory mucosa of panting species has led to differences in AQP localization is unknown. Using immunohistochemistry, we report the localization of AQP1, 3, and 5 in the nasal respiratory mucosa of sheep being exposed to ambient temperatures of ~21 °C or ~38 °C for 4.5 h before death (n=3/treatment). Exposure to either treatment resulted in panting. While exposure to ~38 °C resulted in a higher respiratory frequency (mean difference: 82 breaths min⁻¹; P<0.001) than exposure to ~21 °C, there was no difference in the localization of AQPs. Connective tissue and vascular endothelial cells expressed AQP1. Glandular acini expressed AQP1 and apically localized AQP5, which was also present in glandular duct cells. Ciliated columnar epithelial cells expressed AQP5 apically and AQP3 basolaterally. Basal cells expressed AQP3. The distribution and co-localization of AQPs in the ovine nasal respiratory mucosa is different to that reported in non-panting species and may reflect the physiological demands associated with enhanced respiratory evaporation. We propose that AQP1, 3, and 5 may constitute a transepithelial water pathway via glandular secretions and across the surface epithelium, which provides a possible means for rapid and controllable water movement in the nasal respiratory mucosa of a panting species.     

Structures of the intermediates in the catalytic cycle of mitochondrial cytochrome c oxidase

Cytochrome c oxidase is the terminal complex of the respiratory chains in the mitochondria of nearly all eukaryotes. It catalyzes the reduction of molecular O₂ to water using electrons from the respiratory chain, delivered via cytochrome c on the external surface of the inner mitochondrial membrane. The protons required for water formation are taken from the matrix side of the membrane, making catalysis vectorial. This vectorial feature is further enhanced by the fact that the redox catalysis is coupled to the translocation of protons from the inside to the outside of the inner mitochondrial membrane. We are dealing with a molecular machine that converts redox free energy into a protonmotive force (pmf). Here, we review the current extensive knowledge of the structural changes in the active heme?copper site that accompany catalysis, based on a large variety of time-resolved spectroscopic experiments, X-ray and cryoEM structures, and advanced computational chemistry.     

Bacterial microbiota in upper respiratory tract of COVID-19 and influenza patients

The upper respiratory tract is inhabited by diverse range of commensal microbiota which plays a role in protecting the mucosal surface from pathogens. Alterations of the bacterial community from respiratory viral infections could increase the susceptibility to secondary infections and disease severities. We compared the upper respiratory bacterial profiles among Thai patients with influenza or COVID-19 by using 16S rDNA high-throughput sequencing based on MiSeq platform. The Chao1 richness was not significantly different among groups, whereas the Shannon diversity of Flu A and Flu B groups were significantly lower than Non-Flu & COVID-19 group. The beta diversity revealed that the microbial communities of influenza (Flu A and Flu B), COVID-19, and Non-Flu & COVID-19 were significantly different; however, the comparison of the community structure was similar between Flu A and Flu B groups. The bacterial classification revealed that Enterobacteriaceae was predominant in influenza patients, while Staphylococcus and Pseudomonas were significantly enriched in the COVID-19 patients. These implied that respiratory viral infections might be related to alteration of upper respiratory bacterial community and susceptibility to secondary bacterial infections. Moreover, the bacteria that observed in Non-Flu & COVID-19 patients had high abundance of Streptococcus, Prevotella, Veillonella, and Fusobacterium. This study provides the basic knowledge for further investigation of the relationship between upper respiratory microbiota and respiratory disease which might be useful for better understanding the mechanism of viral infectious diseases.     

Respiratory water flow and production of mucus in the cushion star, Pteraster tesselatus Ives (Echinodermata: Asteroidea)

Histological analysis revealed three types of mucous cells present in the tissues of Pteraster tesselatus Ives. They were all unicellular in structure and each was restricted to certain areas of the anatomy. Mucus produced by these gland cells was forced out onto the aboral surface of Pteraster by water pressure generated within the nidamental cavity (respiratory chamber).Water flow in and out of the respiratory chamber was powered both by muscle contractions and a complex network of overlapping ossicles. Ambient sea water was allowed into the respiratory chamber only through large pores lining the ambulacral groove. Expulsion of respiratory water out of the chamber was by either one of two different pathways. In defence, water and secreted mucus were forced out of the numerous spiracular openings that perforate the supradorsal membrane. When, on the other hand, the sea star was not in a defensive posture, water was simply passed out through the centrally located osculum.     

The cardiac responses of the scallop Pecten maximus (L.) to respiratory stress

Heart activity of Pecten maximus (L.) has been recorded during various forms of experimentally induced respiratory stress. There was considerable variation in the responses of individual scallops but bradycardia generally occurred in response to all forms of respiratory stress, with the rate of fall in heart rate dependent upon the severity of hypoxia.When oxygen tension declined slowly in a closed respirometer there was regulation of both heart rate and oxygen consumption. The critical tension, P_c, for oxygen consumption lay between 70 and 80 mm Hg, and corresponded with a slight regulatory upswing of the heart rate, whereas the P_c for heart rate was much lower at 20–30 mm Hg. Sudden transfer to deoxygenated water for 3 h resulted in very rapid bradycardia and there was a rapid recovery and initial overshoot of the normal rate on return to well-oxygenated sea water. Aerial exposure for 3 h produced more gradual bradycardia followed by gradual recovery on return to sea water.The results of this work are compared in some detail with previous work on other species of bivalve from different geographical areas and habitats, and the mechanisms controlling cardiac and respiratory regulation are discussed. It is concluded that there are few clear-cut general differences between littoral and sublittoral species in their behavioural and physiological adaptations to hypoxia; the main distinguishing feature of littoral-adapted species is their ability to control air-gaping. Changes in heart activity generally indicate variations in metabolic rate, the speed at which the metabolic rate may be altered reflecting the degree of adaptation to the littoral environment.     

The AgI/II Family Adhesin AspA Is Required for Respiratory Infection by Streptococcus pyogenes

Streptococcus pyogenes (GAS) is a human pathogen that causes pharyngitis and invasive diseases such as toxic shock syndrome and sepsis. The upper respiratory tract is the primary reservoir from which GAS can infect new hosts and cause disease. The factors involved in colonisation are incompletely known however. Previous evidence in oral streptococci has shown that the AgI/II family proteins are involved. We hypothesized that the AspA member of this family might be involved in GAS colonization. We describe a novel mouse model of GAS colonization of the nasopharynx and lower respiratory tract to elucidate these interactions. We used two clinical M serotypes expressing AspA, and their aspA gene deletant isogenic mutants in experiments using adherence assays to respiratory epithelium, macrophage phagocytosis and neutrophil killing assays and in vivo models of respiratory tract colonisation and infection. We demonstrated the requirement for AspA in colonization of the respiratory tract. AspA mutants were cleared from the respiratory tract and were deficient in adherence to epithelial cells, and susceptible to phagocytosis. Expression of AspA in the surrogate host Lactococcus lactis protected bacteria from phagocytosis. Our results suggest that AspA has an essential role in respiratory infection, and may function as a novel anti-phagocytic factor.     

AdHu5Ag85A Respiratory Mucosal Boost Immunization Enhances Protection against Pulmonary Tuberculosis in BCG-Primed Non-Human Primates

Persisting high global tuberculosis (TB) morbidity and mortality and poor efficacy of BCG vaccine emphasizes an urgent need for developing effective novel boost vaccination strategies following parenteral BCG priming in humans. Most of the current lead TB vaccine candidates in the global pipeline were developed for parenteral route of immunization. Compelling evidence indicates respiratory mucosal delivery of vaccine to be the most effective way to induce robust local mucosal protective immunity against pulmonary TB. However, despite ample supporting evidence from various animal models, there has been a lack of evidence supporting the safety and protective efficacy of respiratory mucosal TB vaccination in non-human primates (NHP) and humans. By using a rhesus macaque TB model we have evaluated the safety and protective efficacy of a recombinant human serotype 5 adenovirus-based TB vaccine (AdHu5Ag85A) delivered via the respiratory mucosal route. We show that mucosal AdHu5Ag85A boost immunization was safe and well tolerated in parenteral BCG-primed rhesus macaques. A single AdHu5Ag85A mucosal boost immunization in BCG-primed rhesus macaques enhanced the antigen–specific T cell responses. Boost immunization significantly improved the survival and bacterial control following M.tb challenge. Furthermore, TB-related lung pathology and clinical outcomes were lessened in BCG-primed, mucosally boosted animals compared to control animals. Thus, for the first time we show that a single respiratory mucosal boost immunization with a novel TB vaccine enhances protection against pulmonary TB in parenteral BCG-primed NHP. Our study provides the evidence for the protective potential of AdHu5Ag85A as a respiratory mucosal boost TB vaccine for human application.     

Fine Particulate Air Pollution and Hospital Emergency Room Visits for Respiratory Disease in Urban Areas in Beijing,China, in 2013

BackgroundHeavy fine particulate matter (PM_2.5) air pollution occurs frequently in China. However, epidemiological research on the association between short-term exposure to PM_2.5 pollution and respiratory disease morbidity is still limited. This study aimed to explore the association between PM_2.5 pollution and hospital emergency room visits (ERV) for total and cause-specific respiratory diseases in urban areas in Beijing.MethodsDaily counts of respiratory ERV from Jan 1 to Dec 31, 2013, were obtained from ten general hospitals located in urban areas in Beijing. Concurrently, data on PM_2.5 were collected from the Beijing Environmental Protection Bureau, including 17 ambient air quality monitoring stations. A generalized-additive model was used to explore the respiratory effects of PM_2.5, after controlling for confounding variables. Subgroup analyses were also conducted by age and gender.ResultsA total of 92,464 respiratory emergency visits were recorded during the study period. The mean daily PM_2.5 concentration was 102.1±73.6 μg/m³. Every 10 μg/m³ increase in PM_2.5 concentration at lag₀ was associated with an increase in ERV, as follows: 0.23% for total respiratory disease (95% confidence interval [CI]: 0.11%-0.34%), 0.19% for upper respiratory tract infection (URTI) (95%CI: 0.04%-0.35%), 0.34% for lower respiratory tract infection (LRTI) (95%CI: 0.14%-0.53%) and 1.46% for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) (95%CI: 0.13%-2.79%). The strongest association was identified between AECOPD and PM_2.5 concentration at lag_0-3 (3.15%, 95%CI: 1.39%-4.91%). The estimated effects were robust after adjusting for SO₂, O₃, CO and NO₂. Females and people 60 years of age and older demonstrated a higher risk of respiratory disease after PM_2.5 exposure.ConclusionPM_2.5 was significantly associated with respiratory ERV, particularly for URTI, LRTI and AECOPD in Beijing. The susceptibility to PM_2.5 pollution varied by gender and age.     

Computer Solutions for Photosynthesis Rates from a Two Pigment Model

A kinetic model for a two pigment mechanism of photosynthesis based on observations made on the red alga Porphyridium cruentum is developed. The model supposes that different products are formed by chlorophyll and phycobilin pigments and that these products react to produce oxygen. The product of the chlorophyll reaction is also rapidly utilized for O₂ consumption both in light and in the dark. Rate equations based on the model reactions were derived and put into an analog computer. The effect of varying parameters on the time course curves for oxygen exchange resulting from the model was studied. Appropriate selection of parameters yielded computer curves which resembled fairly closely the oxygen exchange curves obtained using Porphyridium. The model showed the Emerson enhancement effect, chromatic transients, “respiratory stimulation,” and other effects observed with live algae.     

Conodont assemblages: A new functional model

A functional model for the conodont apparatus is proposed based on Carboniferous bedding plane assemblages. It is proposed that the conodont assemblage functioned as a filter feeding and respiratory organ in organisms of unknown affinities, and that the organisation of elements in the assemblage genus Scottognathus can be used as a basic plan for interpreting the arrangement of conodont elements in other assemblages. In our model the Platform Blades opened and closed the anterior end of the system, the sieve consisted of Arched Blades, Pick-shaped Blades (assemblage genera Lewistownella and Lochriea) and the main cusps of the Elongate Blades; the denticulated bars of Elongate Blades and Pick-shaped Blades (form genera Scottognathus and Westphalicus) acted as a support for ciliated tissue. A radial and bilateral arrangement for the Elongate Blades is presented and discussed. Using this model as a guide we have reconstructed the assemblage genus Duboisella.The success of conodont organisms is attributed to the genetic plasticity of elements of the filter respiratory system, which enabled the system to adapt to evolutionary changes in the marine plankton. Ideas for further research are presented. In this account we have chosen to refer to the morphological form of conodont elements (Rhodes, 1954) rather than to the form generic and specific names assigned to them in the literature, e.g., we use the term Elongate Blades, instead of Hindeodella.